Question

The identification symptoms for pebrine disease in 4th and 5th instar larvae of mulberry silkworm is:

• A. Blue spots over the body
• B. Black spots over the body
• C. Yellow spots over the body
• D. Black and yellow spots over the body

Hint:

The word Pebrine comes from the French word for "pepper", which refers to the characteristic diagnostic black pepper-like spots on infected 4th and 5th instar larvae.

Answer 1

The Correct Option is B

Step 1: Understanding the Concept:
Pebrine is a highly contagious, transovarially transmitted disease in silkworms caused by the microsporidian parasite Nosema bombycis.

Step 2: Detailed Explanation:
During the late larval stages (4th and 5th instars), the diagnostic symptom of a pebrine infection is the appearance of tiny, irregular, pepper-like black spots over the body of the silkworm.
The larvae also show sluggishness, unequal growth, and fail to spin cocoons properly.
Due to this distinct "peppered" appearance, Louis Pasteur named it Pebrine (from the French word 'pébré' meaning pepper).

Step 3: Final Answer:
The key symptom is the presence of black spots over the body, which is option (B).